Bring ¼ cup bone broth to a rolling simmer. Add sliced leeks and sauté until tender. Add potatoes and peas with remaining bone broth. Bring to a boil, then reduce to medium high heat, stirring frequently. Nestle sausages in peas and continue cooking until sausages are cooked through, and peas and potatoes are tender. Remove from heat. Stir in parsley and tomatoes. Season with salt and pepper to taste.